Process and apparatus for the refining of fibers used in the manufacture of paper



March 28, 1967 s. JACQUELIN 3,311,308

PROCESS AND APPARATUS FOR THE REFINING OF FIBERS USED IN THE MANUFACTURE OF PAPER Filed July 14, 1964 2 Sheets-Sheet 1 Fig.1 F/.2 VD

March 28, 1967 JACQUELIN 3,311,308

PROCESS AND APPARATUS FOR THE REFINING OF FIBERS USED IN THE MANUFACTURE OF PAPER 2 Sheets-Sheet 2 Filed July 14, 1964 United States Patent 0 3,311,308 PRGCESSE AND APPARATUS FQR THE REFlNlNG 0F FIEERS USES IN THE MANUFACTURE file PAPER Guy Jacqueiin, Grenoble, France, assignor to Centre Technique dc llndustrie ties Papiers, Cartons et Celluloses, Grenoble, France Filed .luiy i4, 1964, Ser. No. 382,540 Claims priority, application France, July 24, 1963, 942,539 10 Claims. (Cl. 241-28) The present invention relates to paper manufacturing and particularly to the refining or beating of fibers used in such manufacturing.

The presently used fiber refining devices, whose func tion is to process fibers in order to permit the production of homogeneous sheets and whose construction is adapted to suit this purpose, are generally formed so as to have two portions which move with respect to each other. The fibers are carried in an aqueous suspension and circulate between these two portions so as to be subjected to a series of mechanical operations: cutting, crushing, scraping, etc. in a more or less prescribed order.

One goal of the present invention is to render these operations more methodical and in particular the scraping, or rubbing operation which is of great importance for a large variety of fibers, particularly short fibers and certain synthetic and regenerated fibers.

Presently used refining systems geenrally comprise a rotor and a stator which more with respect to one another and whose surfaces carry blades designed to produce the desired action on the material being processed and to permit the circulation and renewal of the fibrous suspension undergoing treatment. If it is desired to eliminate the cutting action, the other mechanical actions and the circulation are produced at the price of a very low efiiciency of energy utilization due to the short period during which fibers are retained between the active surfaces of the system and due also to the uncontrolled turbulences which inevitably develop in the region between this stator and rotor.

it is one object of the present invention to eliminate the above noted difiiculties.

It is another object of this invention to refine fibers for paper making by means which provide an eificient utilization of energy.

Yet another object of the invention is to produce a highly effective refining of fibers by a relatively simple process.

A still further object of this invention is to produce an effective refining action with the aid of simple and dependable means.

The present invention involves a process for refining suspensions of natural, synthetic or regenerated fibers characterized by the fact that a certain volume of suspension is compressed in a space at least one wall of which forms a retaining element which serves to retain the fibers and to allow the passage of a large part of the suspension liquid, the retained mass is compressed in order to produce a concentrated, humid fiber mass which is subjected to a rubbing action and then to a pressure drop, these steps being performed cyclically and automatically.

The present invention also involves novel apparatus for effecting the above-described process, this apparatus being essentially characterized in that it comprises at least one work space into which the fibrous suspensions is introduced, which space comprises a plurality of walls at least one of which forms the fiber retaining element, the walls being movable with respect to one another as to alternately diminish and increase the volume of said work space and so as to exert a rubbing action on the fibers.

In a first embodiment of the apparatus of this invention, the space into which the fiber suspension is introduced, in order to undergo the successive operations of concentration by compression, rubbing, and expansion by decompression, is defined by a grill-work, or grating, which forms the retaining element for a large proportion of fibers while permitting the passage of the suspension medium along with the smallest fiber particles, and by a solid element the active surface of which is substantially parallel to the surface of the retaining element, one of the two elements being movable with respect to the other, by means of both a rotary movement about an axis which forms the common axis of symmetry of both elements and an oscillatory translational movement along said axis so as to permit the performance of the rubbing operation.

In accordance with another characteristic of this embodiment, the movable element comprises means for constricting the input and output passages of the apparatus during the periods when the movable element approaches the retaining element in order to equalize the treatment of the fibrous suspension by effectively isolating one part of the suspension volume during the periods when it is being compressed and rubbed.

In a second embodiment of the present invention, the space into which the fiber suspension is introduced, in order to undergo the successive operations of concentration by compression, rubbing, and decompression, is defined by a grillwork capable of undergoing an alternative movement, and a solid element which is rotatable about an axis perpendicular to the direction of the aforesaid alternating movement.

In the case where several treatment spaces are used, all of which spaces may be defined by either one of the embodiments described above, the flow return regions, in which the suspension liquid flowing from the treatment spaces is alternately collected from the work spaces and supplied thereto, are preferably spaced in communication with one another.

A third embodiment of the present invention envisions the formation of the above-noted work space by a pair of deformable elastic walls mounted on either the stator or rotor element of a rotating assembly, said walls cooperating with a grill-work mounted on the other of said elements, a suspension medium reflux space being provided beyond said grill-work, and the profile of the grillwork being such that it provokes cyclic deformations of said walls in such a Way that the work space alternately diminishes and returns to its original volume.

The above-mentioned grill-work is provided with openings whose form is such as to permit the passage of the suspension medium and the smallest fiber particles while retaining a large percentage of the fibers in such a way as to induce the formation of a more or less uniform layer of fibers upon which the rubbing action will be effected.

The surfaces between which there exists a continuous relative movement do not include any sharp blades capable of damaging the fibers and the circulation of the fiber suspension between the friction surfaces is produced by an alternating widening and narrowing of the distance between these surfaces. This alternating movement, which could be a uniform movement of one or both surfaces, or of only certain parts of one or both surfaces, presents a double advantage:

(a) It creates a cyclic compression and decompression of the fiber suspension, provoking a cyclic flow and reflux of the suspension liquid through the grill-work so as to promote alternately the compression of the fibers on the active surfaces of the work space and the returning of the fibers into suspension after the rubbing operation, and

(b) It permits the advance of the suspension between the active surfaces of the apparatus, which apparatus can be staggered in time so that the suspension liquid passing through the grill under the influence of a compression action in one work area will be in communication with the reflux space of another work area which is simultaneously passing through a decompression, or reflux, phase. This arrangement would also be beneficial since it would permit part of the energy used to form a fiber layer in one work area to be used to re-immerse a fiber layer in suspension in another work area. When one area is undergoing a compression (due to a moving together of its walls), another is experiencing a decompression (due to a moving apart of the walls), with the result that one portion of the liquid in the reflux volume moves alternately from one work area to another.

During the times when the friction surfaces are moving towards one another, the compression action which they exert not only causes the suspension liquid to pass through the grill-work but also tends to force it through the inlet and outlet passages of the apparatus. Since this latter tendency can have the effect of reducing the efficiency of the apparatus and inhibiting the proper formation of the fiber layers, its influence is reduced as has been mentioned above a throttling of the inlet and outlet openings of the apparatus at the start of the movement together of the active surfaces so as to practically isolate one portion of the suspension volume during the compression operation. The suspension, being thus essentially isolated from these passages, can be efiiciently forced against the retaining grill. This isolation which is more or less total, could be produced automatically during the course of the compression movement of the active surfaces in order to give a uniformity to the operations performed on the fibrous suspension.

Before turning to the detailed description of the various illustrated embodiments of the present invention, it would be worthwhile to note that, among the important features of the present invention, the following are of particular significance:

(a) The fibers are treated between surfaces which carry neither sharp blades not rigid indentations;

(b) The circulation of the fibers is facilitated by the cyclic variation of this volume of the work area, this variation being produced either by displacement or by deformation of the fiber treating surfaces; and

(c) The fibers are formed into a concentrated layer prior to rubbing in order to render the rubbing operation more effective.

These and other objects, characteristics and advantages of the present invention, will become more readily apparent from the following detailed description of the embodiments shown in the attached drawings, in which:

FIGS. 1 and 2 are pictorialized cross-sectional views of one embodiment of the present invention in two different operating positions;

FIG. 3 is a longitudinal crosssectional view of one variant of the embodiment of FIGS. 1 and 2;

FIG. 4 is a longitudinal cross-sectional view of another variant of the apparatus of FIGS. 1 and 2;

FIG. 5 is a longitudinal cross-sectional view of a modifieation of the embodiment of PEG. 3;

FIG. 6 is a pictorialized cross-sectional view of apparatus constituting another embodiment of this invention; a

FIG. 7 shows a simplified axial cross-sectional view of a further embodiment of the present invention;

FIGS. 8 and 9 are cross-sectional views of two variants of the embodiment of FIG. 7; and

FIG. 10 is a longitudinal cross-sectional view of still another variation of the embodiment of FIG. 7.

In the various figures, like elements are given the same reference numbers.

Referring firstly to FIG. 1, there is shown an embodiment of the present invention capable of carrying out the process described earlier and comprising a housing 1 furnished with a fiber suspension inlet 2 and an outlet 3 for the emission of the suspension of treated fibers. Within housing 1 is disposed a fixed grill, or grill-work 4, which serves as the fiber retaining element, and a disc 5 whose active surface is essentially parallel to grill 4, the disc 5 being rigidly mounted on a power shaft 6. Disc 5 is thus connected so as to be driven in rotation by shaft 6 when the latter is connected to, and driven by, any suitable motive source (not shown). Housing 1 is mounted on a suitable oscillatory device (also not shown) which permits it to experience and up-and-down movement parallel to the longitudinal axis of shaft 6 so as to cause grill 4 to alternately move towards and away from disc 5.

The space thus created between grill 4 and disc 5 constituted the work, or treatment, area 7 for the apparatus and the space 8 below the rill is the reflux region into which the suspension liquid passes when disc 5 tap proached grill 4 and from which the liquid returns when disc 5 moves away therefrom in order to give the fibrous suspension the consistency required to permit it to circulate freely and to pass out of passage 3 after treatment. Space 8 is in communication with an expansion volume (not shown fully but indicated partly by the vertical pipe extending downward from the bottom of region 8) which can either be open to the atmosphere or closed so as to contain a volume of gas under a controllable pressure. Disc 5 is also rigidly connected to an inlet throttle 9 constituted by a frusto-conical segment which serves to automatically throttle the end of inlet pipe 2 when disc 5 is moving towards grill 4. In addition, disc 5 is so placed that its peripheral edge serves to throttle the opening of outlet passage 3 when the disc moves towards grill 4. The position of these throttling elements when disc 5 is near grill 4 is shown in FiG. 2. In this way, the suspension liquid is practically isolated from the inlet and outlet passages, during the period when the work area '7 is being reduced and is thus effectively forced through grill 4 during this period.

It should be appreciated that the amplitude and frequency of the oscillatory motion between elements 4 and 5 are variable and are adjusted as a function of both the material being treated and the particuiar results desired.

The grill 4 contains a series of openings, having any desired shapes whose dimensions are preferably made smaller than the average fiber length and may be, for example of the order of one millimeter. The distance between these openings may be of the order of the length of these fibers, this being for example, in the range of l to 2 millimeters. The openings, as has been noted above, may be of any desired shape and may, for example, be in the form of narrow slits whose length may be greater than that of the fibers.

The operation performed by the device of FIGS. 1 and 2 takes place in the following manner:

The apparatus is initially in the state shown in FIG. 1 with the fibrous suspension extending between disc 5 and grill 4. As the disc is urged toward grill 4 by the movement of housing 1, the inlet and outlet passages are throttled and the suspension liquid is forced through the grill openings into area 8, forming a layer of fibers on the upper surface of the grill. The disc then compresses the suspension and, when it reaches the position shown in FIG. 2, its rotation produces a rubbing action on the fiber layer on grill 4. The disc 5 then moves away from the grill producing a pressure drop which causes a portion of the suspension liquid to return from region 8 to the work area in order to return the treated fibers into suspension. At the same time, the rotation of disc 5 induces a rotating motion of the suspension which produces a centrifuged action urging the suspension radially outward into outlet passage 3, thus effecting the evacuation of the suspension of treated fibers from the apparatus.

Referring now to FIG. 3, there is shown a variation of the above-described structure on which both faces of movable disc 5 are utilized, each cooperating with a different work area 7a, 717 so as to treat two volumes of suspension liquid at the same time. This embodiment also includes two grills 4a, 4b and two reflux areas 34/, 3b, a respective one of each being associated with each or" said work areas.

In this device there are provided two inlet passage 2a, 217, one for each work area, and only one outlet passage 3. With this arrangement, when the disc is approaching one grill, it is moving away from the other so that suspension liquid being forced through the one grill into its respective reflux space circulates to the other reflux space where the decompression in the work area associated with the other grill draws this liquid through the other grill to return the already treated fiber layer into suspension. There are thus produced two simultaneous treatment cycles which occur in phase opposition, the result of this double action significantly improving the power utilization efliciency of the apparatus.

It should also be noted from the drawing that the movement of housing automatically produces an alternate throttling and de-throttling of the inlet and outlet passages, with respect to each work area, with the throttling of the passages with respect to one work area being in phase opposition to the throttling with respect to the other work area.

In FIG. 4 is shown a variation of the above-described embodiment in which the grill elements 4a, 4b are mounted so as to be given a rotating movement by shaft 6. These grills are rigidly mounted on disc 5, the latter having a series of passages arranged therein to permit the passage of liquid from the openings in one grill to the openings in the other grill. These passages are also in communication with each other (not shown) and form the reflux region for the unit. The oscillatory movement of the device is produced by the movement of housing 1 and in this embodiment it is the inner flat walls of the housing which serve as the active surfaces of each Work area and thus replace the function served by the disc surfaces in the preceding embodiments. The operation of this device is similar to that of the FIG. 3 apparatus: as screen 46 moves towards its associated housing wall liquid is forced through disc 5, producing a fiber-layer on grill 36 and returning the treated fiber layer on grill 4a into suspension; when screen db is nearest its housing wall, the rotation of disc 5 causes this housing wall to produce the desired rubbing action on the fiber layer on grill 4-1); when the rubbing phase has been completed, housing} moves upward, causing the cycle to be repeated in the lower work area.

The embodiments described above have been given only by way of example and it should be appreciated that they could be easily modified, if conditions make it desirable, so that both surfaces of each work area are movable, the only condition being that a relative movement exist between them so as to create the desired compression and rubbing operations. It should also be appreciated that the above-described embodiments could be modified so that both active surfaces comprise retaining grills with the fibers being divided between the two grills in any desired proportions, each grill having associated cavities for receiting liquid and being disposed to permit the reflux of the liquid after the rubbing operation.

The shape of the rubbing surfaces is not limited to the flat configuration shown in the preceding figures, but have any other form, so long as they are symmetrical with the axis of rotation of the dev'ce. One such form is shown in FIG. 5 where the rotating member is constituted by two frustoconical sections 9a, 9b. These surfaces could equally well be cylindrical, spherical, etc. or they could have several portions each conforming to a different one of these shapes. In this embodiment illustrated the apparatus executes a double action similar to that performed by the FIG. 3 device and comprises a pair of grills 4a, 411 each of which cooperates with one of tl 2 G surfaces 9a, 9b to form a work area and each of which is shaped so as to be parallel to its respective surface 9a or 9b. Reflux spaces are provided behind the grills and these spaces communicate with one another through canal i in a manner analogous to that shown in FIG. 3.

As is true for the previously described embodiments, the presence of the retaining grills permits the formation of more or less uniform fiber layers and the formation of these fiber layers is aided by the approaching movement of the rubbing surface. The fibrous suspension is thus forced against the grill by this movement and the reflux space on the other side of the grill permits the flow of liquid out of the work area. After the rubbing operation, the two active surfaces of the work area move away from one another, creating a decompression in the work area which urges the liquid to flow back into this work area, thus facilitating the return of the treated fibers into suspension.

The power absorbed by the apparatus varies from one operating phase to another, the rubbing operation requiring more power than any of the other operations. In order to eliminate excessively sharp changes in power demand, several work areas could be operated by the same motor source, with the process in each area being staggered in time with respect to the processes in the other areas in order to create a more uniform load on the power source. With this arrangement it would be possible to improve the ei'ficiency of the apparatus by connecting together the reflux spaces associated with each work area in order to permit the energy used to drive liquid out of the work areas undergoing compression to aid the reflow of. liquid into work areas experiencing decompression.

These alternating movements of the active surfaces facilitate, not only the formation and re-suspenslon of the fiber layers, but also the circulation and inflow of the fibrous suspension to be treated. Finally, supplementary means, such as the throttle 9 and the disc 5, automatically produce a more or less complete closing of the outlet passages of the device during the compression operation so as to permit a more uniform treatment of the fibers. It should be noted however that the provision f these latter means is not indispensable to the carrying out of the basic process of the present invention.

It should also be evident that the provision of appropriate driving means for the active elements of the work areas will erve to eliminate sudden changes in speed at the commencement of the rubbing operation. For this purpose one may use hydraulic driving means, for example.

It should be noted that the quality of the treated fiber suspension is improved by the fact that none of the above-described devices comprise any sharp-edge elements in their respective work areas to cut the fibers under treatment.

Still another form which the present invention may take is shown in FIG. 6 in which the apparatus performs all of the operations carried out by the preceding structures. This apparatus comprises a rotating drum, or rotor, 11 around the periphery of which are disposed one or several work areas. Each work area is formed with a housing 12 in the walls of which are arranged an inlet passage 13 for the suspension of fibers to be treated and an outlet passage =14 for the treated suspension. Within each housing 12 is movably disposed a unit carrying a fiber retaining grill 15 conforming to the shape of the penipheral surface of'rotor 11 and a reflux space 16 for the suspension liquid. This unit is mounted to slide in its housing so as to move alternately toward rotor 11, to effect a compression on the suspension of fibers being treated, and away from the rotor, to produce a pressure decompression in the work area 17 between the rotor and the grill and cause the reflux of suspension liquid from space 16 to the work area. Two work areas are shown in this embodiment having a tubing 18 joining their reflux spaces. The two movable units are mounted for staggered operation so that when one work area is undergoing compression, the other is experiencing a decompression and a portion of the suspension liquid is passing through tube 18 from the reflux space of the former area to that of the latter area. Thus the force necessary to cause compression in one work area is utilized to facilitate the circulation of the suspension fluid. The inlet and outlet passages, 13 and 14', respectively, are positioned in the housing walls so that their openings into housing 12 are effectively throttled by the compression movement of the unit carrying grill 15. Thus the operation of this apparatus is directly analogous to that of FIG. 5.

FIGS. 7 to show variations of yet another embodiment of the present invention permitting the compression of a suspension mass in a space one wall of which forms a retaining element which allows the passage of most of the suspension liquid in order to form a fiber layer which is first submitted to a rubbing action and then subjected to a pressure decompression provoking a reflux of the suspension liquid which returns the treated fibers into suspension.

In the devices now to be described, the compressions and decompressions of the suspension are obtained, not by an alternating linear movement of the active surfaces of the work area, but by deformation of the walls of one or several work areas under the action of appropriately placed obstacles in the rotating path of the work area, which obstacles act on the deformable walls in a manner which will be described below.

The apparatus shown in FIG. 7 comprises a cylindrical stator element 19 and a rotor 20 carrying a plurality of tapered deformable vanes 21 made of elastic material (rubber, neoprene, etc.) said rotor being mounted co axially with said stator so that the wide rounded ends of the vanes 21 rub against the stator. Retention grills 22 are rigidly fastened on the inner wall of stator 19 so as to form reflux spaces 26 between themselves and the stator wall. An input passage 23 for the fibrous suspension is provided in one base of rotor 19 and an outlet passage 24 for the treated suspension is provided in the other base thereof.

Between each adjacent pair of vanes 21 there exists a work area 25 which is analogous, for example, to the work area 7 of the FIG. 1 device, just as the reflux spaces 26 are analogous to the reflux space 8 of that earlier figure.

The treatment of the fibers is carried out by a series of operations similar to those performed in the devices described above. As each vane 21 comes in contact with one of the grills, it is flexed towards rotor 20 in such a way as to decrease the volume of the work area 25 for r which it forms the leading edge. This action causes a compression of the suspension in that work area, forcing the suspension liquid through the grill 22 and forming a fiber layer on that grill. The liquid forced into space 26 is drawn forward and flows across the forward portion of grill 26 into a work area ahead of the area undergoing compression, this action being created by the decompression produced in this forward work area, when its forward vane 21 leaves the grill 22 and reassumes its position against stator 19. The rubbing action on the fiber layer is produced by vanes 21, which vanes also function to urge the layer forward to the front end of grill 26 where they will be re-suspended by the liquid flowing from the succeeding work areas then undergoing compression. After having been treated on both grills, the fiber suspension is evacuated through passage 24.

Although two grills 22 have been shown in the device of FIG. 7, it should be appreciated that any number of grills, including one, may equally well be used.

FIG. 8 shows a variation of the FIG. 7 apparatus which only differs therefrom by the fact that grill 22a is a continuous element shaped so as to form a uniformly spaced series of reflux spaces and so as to create an alternating succession of compression and decompression regrons.

FIG. 9 shows a variation of the FIG. 7 device in which the positions of the vanes 21 and grills 22a are reversed so that the former are attached to stator 19 and the latter rotate with rotor 29. operation of this device is essentially identical with that of the devices of FIGS. 7 and 8.

FIG. 10 shows yet another variation of the structure of FIG. 7 in which a stator 19a is constituted by a fiat disc to which are attached a series of vanes 21 and in which a rotor Zita is also constituted by a disc to which is connected a fiber retaining grill 22a. Only a portion of these discs is shown in the figure. Disc 20a is rigidly connected to shaft 6 so as to be rotated by the shaft under the action of a suitable power source (not shown). The suspension of fibers to be treated is brought into the device through input passage 27 and the exit of the treated fibers is made through a passage at the periphery of the stator-rotor assembly and because only a limited portion of the apparatus is shown, this outlet does not appear in the figure. The operation of this device is identical with that of the devices shown in FIGS. 7-9; alternating compressions and decompressions are produced in each work area by the cyclic deformations of vanes 21.

In the apparatus shown in FIGS. 7 to 10, the circulation of the suspension and the fibers is facilitated by the continuous unidirectional movement of the deformable vanes which form the movable walls of the work areas. The various phases of operation described above occur in a continuous fashion and overlap slightly on one another. Thus the rubbing operation commences before the compression phase has been terminated, with the contact surface between the fibers and the vanes increasing with the deformation of the work area. Similarly the friction operation continues, diminishing progressively, during the initial portion of the decompression phase.

The supplying and evacuation of the fibrous suspension can be made at the level of the work areas by means of pumps, gravity or any other means. The surfaces upon which the deformable elements are disposed could have shapes other than cyiindric; they could be conic, frustoconic, spherical, toroidal or a combination thereof, the examples given not being limitative.

Moreover, embodiments of the present invention could be made to combine the techniques of the various embodiments described above. For example, one could construct devices utilizing the deformable elements of FIGS. 7 to 10 and means such as those shown in FIGS. 1 to 5 for producing the alternating compression and decompression actions.

It has been found that the refining apparatus described above possesses, in addition to others, the following important advantages over the prior art:

They realize a decrease in turbulence and a more effective control of fluid movement, thereby contributing to a more efficient utilization of energy;

The treatment of fibers is more uniform and a larger proportion of the fibers introduced into the apparatus undergo a rubbing action than is the case in the prior art blade-type refining devices;

The improved control of the treated operations eliminates the prior art requirement of several passages of the suspension through the device;

The duration, and not only the pressure, of the rubbing operation can be accurately regulated, While in the prior art blade-type devices the fibers are compressed between two blades for only a short time, which is a function of blade width, and are quickly returned into suspension. In the apparatus of the present invention, the duration of the rubbing operation can be regulated at Will so as to reduce to a minimum the number of passages of the fibers through the treatment cycle. Also the ability to vary the distance between friction elements, as a function of time, permits an extremely flexible regulation of the treatment operation; and

The tendency to cut the fibers being practically nonexistant in the embodiments of the present invention,

these devices are particularly well adapted to the treatment of short fibers to develop their paper properties to the maximum, as well as to the treatment of certain synthetic and regenerated fibers which are relatively fragile and in which an abundance of fibrils could be developed without the occurrence of marked shrinkage.

The above described embodiments could also be modified by replacing the grills with sheets of woven material, fiber material, or any other body permitting the passage of the suspension liquid. It should also be noted that the reflux of liquid during the decompression phase of the process is not indispensable, particularly in the embodiments using deformable vanes. In some cases the treated fiber layer could be carried towards the outlet passage by the friction surfaces and could there be reimmersed in suspension.

Many other modifications may occur to those skilled in the art without departing from the spirit of the present invention and it is therefore intended that the coverage of the present invention be limited only by the scope of the appended claims.

I claim:

1. The process of refining fibers in a liquid suspension comprising:

(a) introducing a volume of suspension in a Work area at least one wall of which is porous to permit the passage of suspension liquid;

(b) decreasing the volume of said work area to force said liquid through said porous wall and to cause the fibers to form a layer on said wall;

(c) bringing a second Wall of said work area in contact with said fiber mass;

(d) causing said second wall to move unidirectionally with respect to said porous wall to effect a rubbing action on said fiber layer;

(e) retracting said second wall to produce a decompression in said work area, said decompression causing said suspension liquid to pass back through said porous wall and to return said treated fibers into suspension; and

(f) evacuating said suspension of treated fibers from said work area.

2. Apparatus for refining fibers in a liquid suspension,

said apparatus comprising:

(a) a housing within which is mounted a porous member separating at least one fiber treatment area from at least one suspension liquid reflux area;

(b) at least one solid wall member defining at least one bounding of said work area and movable with respect to said porous member;

(c) means for producing a relative movement between said solid wall member and said porous member so as to alternately decrease and increase the volume 1 3 of said treatment area and so as to exert a rubbing action on fibers disposed on said porous member; and

(d) passages for introducing said suspension into said treatment area for evacuating it therefrom.

3. Apparatus as recited in claim 2 wherein said porous member comprises a flat grill-work; said solid wall member is flat and is oriented parallel to said grillwork; and said means for moving is connected to produce relative movements between said grill work and said wall members which movements are both perpendicular to, and parallel to the surface of said grill-Work.

4. Apparatus as recited in claim 3 wherein said means for moving comprises oscillating means for moving said grillwork in a direction perpendicular to its surface and rotating means for rotating said wall member in a plane parallel to said surface.

5. A device as recited in claim 2 comprising a plurality of said fibers treatment areas and reflux areas, each of said reflux areas being associated with a respective one of said treatment areas, and all of said reflux areas being interconnected.

6. Apparatus as recited in claim 3 wherein said means for moving comprises oscillating means for moving said grill-work in a direction perpendicular to its surface and rotating means for rotating said wall member about an axis perpendicular to said surface with said Wall member being concentric about said axis.

7. Apparatus as recited in claim 2, wherein said Wall member is in the form of a plurality of solid elastically deformable vanes arranged along the surface of, and touching, said porous member, and said means for moving is connected to said vanes to cause them to move unidirectionally over the surface of said porous member.

8. Apparatus as recited in claim 7 wherein said porous member undulates along a planar surface.

9. Apparatus as recited in claim 7 wherein said porous member undulates along a cylindrical surface.

19. Apparatus as recited in claim 2 wherein said solid Wall member comprises means for constricting said passages when said means for moving is causing the volume of said treatment area to decrease.

References (Iited by the Examiner UNITED STATES PATENTS 2,156,320 5/1939 Sutherland 24128 2,947,655 8/1960 Eberhardt 241-28 3,119,570 1/1964 Sandison 24173 WILLIAM W. DYER, 111., Primary Examiner. R. I. ZLOTNIK, Assistant Examiner. 

1. THE PROCESS OF REFINING FIBERS IN A LIQUID SUSPENSION COMPRISING: (A) INTRODUCING A VOLUME OF SUSPENSION IN A WORK AREA AT LEAST ONE WALL OF WHICH IS POROUS TO PERMIT THE PASSAGE OF SUSPENSION LIQUID; (B) DECREASING THE VOLUME OF SAID WORK AREA TO FORCE SAID LIQUID THROUGH SAID POROUS WALL AND TO CAUSE THE FIBERS TO FORM A LAYER ON SAID WALL; (C) BRINGING A SECOND WALL OF SAID WORK AREA IN CONTACT WITH SAID FIBER MASS; (D) CAUSING SAID SECOND WALL TO MOVE UNIDIRECTIONALLY WITH RESPECT TO SAID POROUS WALL TO EFFECT A RUBBING ACTION ON SAID FIBER LAYER; (E) RETRACTING SAID SECOND WALL TO PRODUCE A DECOMPRESSION IN SAID WORK AREA, SAID DECOMPRESSION CAUSING SAID SUSPENSION LIQUID TO PASS BACK THROUGH SAID POROUS WALL AND TO RETURN SAID TREATED FIBERS INTO SUSPENSION; AND (F) EVACUATING SAID SUSPENSION OF TREATED FIBERS FROM SAID WORK AREA. 